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Binding affinity between HP1-HOAP interacting
protein (HipHop) and telomere maintenance
proteins Modigliani & Verrocchio in Drosophila
melanogaster through co-immunoprecipitation
and Western blot analysis
JORDAN DAVIS
BNFO 300
Terminology
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HP1-HOAP-interacting protein (HipHop)
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Modigliani (moi)
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Is a subunit protein of the terminin complex, but individual role is still unknown
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Is exclusively located at the telomeres
Verrocchio (ver)
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Is a subunit protein of the terminin complex, but individual role is still unknown
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Is exclusively located at the telomeres
Terminin
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Protein complex which includes Modigliani, Verrocchio, and HipHop
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Potential unknown protein subunits?
Shelterin
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Telomere maintenance protein, critical for protection of telomeres and prevention of chromatid fusion
Human analog for terminin protein complex
Telomere
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DNA nucleotide sequence at each end of chromatid
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Telomeres act as caps which protects end of each chromatid from deterioration
Raffa, Grazia D., et al. "Organization and evolution of Drosophila terminin: similarities and differences between Drosophila and human telomeres."Frontiers in oncology 3 (2013).
Raffa, Grazia D., et al. "ORGANIZATION AND MAINTENANCE OF DROSOPHILA TELOMERES: THE ROLES OF TERMININ AND NON-TERMININ PROTEINS." ЦИТОЛОГИЯ 55.3 (2013): 204-208.
Raffa, Grazia D., et al. "Terminin: a protein complex that mediates epigenetic maintenance of Drosophila telomeres." Nucleus 2.5 (2011): 383-391.
Raffa, Grazia D., et al. "Verrocchio, a Drosophila OB fold-containing protein, is a component of the terminin telomere-capping complex." Genes & development24.15 (2010): 1596-1601.
Location: Telomeres
U.S. Department of Energy Human Genome Program. SierraSciSPA
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Made of nucleoprotein complexes and are located
eukaryotic chromosome ends
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Are capped at the end of each chromatid
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Used as a buffer to protect DNA sequences
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Prevents chromosome end-to-end fusion
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Fruit fly telomeres are capped by protein complex
terminin
Raffa, Grazia D., et al. "Organization and evolution of Drosophila terminin: similarities and differences between Drosophila and human telomeres."Frontiers in oncology 3 (2013).
Raffa, Grazia D., et al. "ORGANIZATION AND MAINTENANCE OF DROSOPHILA TELOMERES: THE ROLES OF TERMININ AND NON-TERMININ PROTEINS." ЦИТОЛОГИЯ 55.3 (2013): 204-208.
Methodology I: Co-Immunoprecipitation assay
I.
The protein mixture will be obtained from the salivary gland
nuclei from drosophila third instar larvae development stage
II.
Retrieve antibody that targets a certain antigen, in this case
we will target HP1-HOAP-interacting protein (HipHop)
III.
Antigen (HP1-HOAP (HipHop)) will bind with the coupled
antibody
IV. After the spin/wash and elute processes I will analyze the
antigens and protein interacting partners to find new
components of the terminin complex in a phage display
assay
Proteins that should interact with HP1-HOAP protein are
*Verrocchio
*Modigliani
*Possible newly found terminin protein subunits yet to be
discovered?
www.piercenet.com/method/co-immnoprecipiatation-co-ip
www.piercenet.com/method/co-immnoprecipiatation-co-ip
Rubin M. Gerald 1988. Drosophila
melanogaster as an Experimental Organism.
Science, New Series, Vol. 240. No. 4858 (Jun.
10, 1988), pp. 1453-1459
Raffa, Grazia D., et al. "Verrocchio, a Drosophila OB fold-containing protein, is a component of the terminin telomere-capping complex." Genes & development24.15 (2010): 1596-1601.
Methodology II: Phage Display assay
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After the sample of antigens and interacting proteins are analyzed from the Co-IP
sample I will begin the phage display assay.
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Phage Display Protocol
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Insert HP1-HOAP (HipHop) gene inside a phage coat protein gene
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This allows for the phage to display the protein the gene encodes on the
outside, while the phage still houses the gene on the inside of the phage
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Proteins that are known to bind with HP1-HOAP (HipHop) such as
Modigliani and Verrocchio should bind with the desired protein
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Unknown proteins that may have been attached with Modigliani and
Verrocchio can potentially be subunit proteins of the terminin complex
yet to be discovered
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After the elute process I will analyze the sample of polypeptides, hopefully
finding new polypeptides that may be critical subunits of the terminin
complex
Dr. Graham Beards – Own work
Phage display process described further in Wolfe et al. (1999)
Wolfe, Scot A., et al. "Analysis of zinc fingers optimized< i> via</i> phage display: evaluating the utility of a recognition code." Journal of molecular
biology 285.5 (1999): 1917-1934.
Raffa, Grazia D., et al. "Terminin: a protein complex that mediates epigenetic maintenance of Drosophila telomeres." Nucleus 2.5 (2011): 383-391.
Expected Outcomes
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I would expect to see expression in Modigliani and Verrocchio. These two telomere
maintenance proteins are known to be apart of the terminin complex within drosophila.
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Measurement: Expression of Modigliani and Verrocchio through a Western blot procedure
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Significance: To reassure that the protein sample that was experimented in Co-IP included the only currently
discovered proteins in the drosophila terminin complex.
I would also expect to see expression in HipHop through western blot analysis
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Significance: Through the Co-Immunoprecipitation and western blot assays I should be reassured that the
antigen HipHop and the interacting partners Modigliani and Verrocchio are apart of the protein complex.

The discovery of new protein subunits through the phage display assay that are a part of the terminin complex in
drosophila that could very well be extremely critical proteins for telomere protection and maintenance
The cons
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The Co-IP method can be used to find specific proteins that are already identified and can shed light on
interactions between said proteins within the complex, but it cannot identify new proteins.
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This is why I include the phage display assay to present a possibility of discovering new protein subunits involved
in the terminin complex
Raffa, Grazia D., et al. "ORGANIZATION AND MAINTENANCE OF DROSOPHILA TELOMERES: THE ROLES OF TERMININ AND NON-TERMININ PROTEINS." ЦИТОЛОГИЯ 55.3 (2013): 204-208.
Raffa, Grazia D., et al. "Terminin: a protein complex that mediates epigenetic maintenance of Drosophila telomeres." Nucleus 2.5 (2011): 383-391.
Raffa, Grazia D., et al. "Verrocchio, a Drosophila OB fold-containing protein, is a component of the terminin telomere-capping complex." Genes & development24.15 (2010): 1596-1601.
Background & Relevance
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Drosophila protein complex terminin is an analogue for the telomere
protecting protein complex shelterin in humans
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Continued analysis of drosophila telomeres opens a gateway for
investigations of human telomere biology
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Novel components of human telomere protection in shelterin may be
discovered by learning interactions between proteins within the terminin
complex, the fruit fly analogue for telomere maintenance and protection
Raffa, Grazia D., et al. "Organization and evolution of Drosophila terminin: similarities and differences between Drosophila and human telomeres."Frontiers in oncology 3 (2013).
Muller H. J. (1938). The remaking of chromosomes. Collect. Net 8, 182–195
Gao, Guanjun, et al. "HipHop interacts with HOAP and HP1 to protect Drosophila telomeres in a sequence‐independent manner." The EMBO journal29.4 (2010): 819-829.
References
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Biessmann, Harald, Steven B. Carter, and James M. Mason. "Chromosome ends in Drosophila without telomeric DNA sequences." Proceedings of the National Academy of Sciences 87.5 (1990):
1758-1761.
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Cenci, Giovanni, et al. "The Drosophila HOAP protein is required for telomere capping." Nature cell biology 5.1 (2002): 82-84.
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Frydrychová, Radmila, et al. "Phylogenetic distribution of TTAGG telomeric repeats in insects." Genome 47.1 (2004): 163-178.
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Gao, Guanjun, et al. "HipHop interacts with HOAP and HP1 to protect Drosophila telomeres in a sequence‐independent manner." The EMBO journal29.4 (2010): 819-829.
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Muller H. J. (1938). The remaking of chromosomes. Collect. Net 8, 182–195
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Nielsen, Lena, and J. E. Edström. "Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats." Molecular and
cellular biology 13.3 (1993): 1583-1589.
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Raffa, Grazia D., et al. "Organization and evolution of Drosophila terminin: similarities and differences between Drosophila and human telomeres."Frontiers in oncology 3 (2013).

Raffa, Grazia D., et al. "ORGANIZATION AND MAINTENANCE OF DROSOPHILA TELOMERES: THE ROLES OF TERMININ AND NON-TERMININ PROTEINS." ЦИТОЛОГИЯ 55.3 (2013): 204-208.

Raffa, Grazia D., et al. "Terminin: a protein complex that mediates epigenetic maintenance of Drosophila telomeres." Nucleus 2.5 (2011): 383-391.

Raffa, Grazia D., et al. "Verrocchio, a Drosophila OB fold-containing protein, is a component of the terminin telomere-capping complex." Genes & development24.15 (2010): 1596-1601.
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Roth, Charles W., et al. "Chromosome end elongation by recombination in the mosquito Anopheles gambiae." Molecular and cellular biology 17.9 (1997): 5176-5183.
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Takada, Shinako, et al. "A TRF1: BRF Complex Directs Drosophila RNA Polymerase III Transcription." Cell 101.5 (2000): 459-469.
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Wolfe, Scot A., et al. "Analysis of zinc fingers optimized< i> via</i> phage display: evaluating the utility of a recognition code." Journal of molecular biology 285.5 (1999): 1917-1934.
Questions?